1. Field of the Invention
This invention relates to an image forming apparatus including a copy machine and printer, which are provided with a interrupt copying function and an energy saving function.
2. Description of the Prior Art
A conventional copying machine includes an image forming device for forming a toner image on a copy sheet and a fuser for fixing the toner image on the copy sheet. However, in use of a heat roll fuser, a large heat capacity is required, and it takes much time to heat the fuser to an applicable temperature. Therefore, normally the fuser is maintained at the applicable temperature so as to permit copying operation to occur at any time.
However, in the conventional copying machine as mentioned above, it is impossible to use electric power effectively. To avoid this problem, another conventional copying machine has been provided with an energy saving function whereby the machine is set in a standby status and the temperature of the fuser is maintained lower than the applicable temperature.
However, the copying machine is generally provided with an interrupt copying function which, by setting an interrupt copying mode during one copy run, permits performing of another copy run.
Accordingly, when the energy saving function is set during the interrupt copying mode, the data related to the copying condition of the previous run is cleared from a memory where it is stored. As the result, it becomes impossible to complete the interrupted copy run after an interrupting run is finished.